gpio: make library immune to error pointers

Most functions that take a GPIO descriptor in need to check the
descriptor for IS_ERR(). We do this mostly in the VALIDATE_DESC()
macro except for the gpiod_to_irq() function which needs special
handling.

Cc: stable@vger.kernel.org
Reported-by: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 11 insertions, 3 deletions

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index f39bf05993e7..570771ed19e6 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1373,8 +1373,12 @@ done:
 #define VALIDATE_DESC(desc) do { \
         if (!desc) \
                 return 0; \
+        if (IS_ERR(desc)) {                                             \
+                pr_warn("%s: invalid GPIO (errorpointer)\n", __func__); \
+                return PTR_ERR(desc); \
+        } \
         if (!desc->gdev) { \
-                pr_warn("%s: invalid GPIO\n", __func__); \
+                pr_warn("%s: invalid GPIO (no device)\n", __func__); \
                 return -EINVAL; \
         } \
         if ( !desc->gdev->chip ) { \
@@ -1386,8 +1390,12 @@ done:
 #define VALIDATE_DESC_VOID(desc) do { \
         if (!desc) \
                 return; \
+        if (IS_ERR(desc)) {                                             \
+                pr_warn("%s: invalid GPIO (errorpointer)\n", __func__); \
+                return; \
+        } \
         if (!desc->gdev) { \
-                pr_warn("%s: invalid GPIO\n", __func__); \
+                pr_warn("%s: invalid GPIO (no device)\n", __func__); \
                 return; \
         } \
         if (!desc->gdev->chip) { \
@@ -2061,7 +2069,7 @@ int gpiod_to_irq(const struct gpio_desc *desc)
          * requires this function to not return zero on an invalid descriptor
          * but rather a negative error number.
          */
-        if (!desc || !desc->gdev || !desc->gdev->chip)
+        if (!desc || IS_ERR(desc) || !desc->gdev || !desc->gdev->chip)
                 return -EINVAL;
 
         chip = desc->gdev->chip;